In modern cooling systems, closing devices such as active grill shutters are used in order to render possible different levels of air flow through a radiator. For example, at a low external temperature or during a warm-up phase of an internal combustion engine, the air flow through the engine radiator can be controlled or regulated.
In winter, closing devices comprising slats or the like can be blocked by snow and ice, this potentially causing only ineffective cooling of the internal combustion engine and therefore potentially leading to a higher consumption of fuel or, under certain circumstances, even to damage to components due to overheating.
U.S. Pat. No. 8,662,569 B2, which describes an apparatus of the generic type, proposes a solution to this problem. An adjusting motor for setting air slats which control a cooling air stream can be operated using two different electric currents. Below an external temperature threshold value with a risk of freezing, a high electric current flows through the motor with a correspondingly higher force for forced movement of the slats, even if these are iced up. Both the motor and the adjusting components of the slats and the slats themselves have to be correspondingly dimensioned for very high forces.
Another apparatus with ice identification of a cooling apparatus with slats and an external temperature sensor is known from U.S. Pat. No. 9,103,265 B2. A Hall sensor serves to detect a shutter position, so that an error signal can be output when slats are blocked. When the shutter is blocked by ice or is undesirably closed, a fan is switched on for cooling purposes, in order to prevent the engine from overheating.
US 2015/0 260 442 A1 describes a method for deicing an external region of a heat exchanger in a motor vehicle. Another method for avoiding freezing in a heat exchanger is known from JP 2013 208 938.